SPI vs UART trade-offs in Embedded C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize SPI communication with the correct clock polarity.

Embedded C

SPI_InitTypeDef SPI_InitStruct = {0};
SPI_InitStruct.ClockPolarity = [1];
// Other initialization code

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AUART_STOPBITS_1

BSPI_POLARITY_HIGH

CUART_PARITY_NONE

DSPI_POLARITY_LOW

Attempts:

3 left

💡 Hint

Common Mistakes

Using UART constants instead of SPI constants for clock polarity.

SPI clock polarity must be set using SPI_POLARITY_LOW or SPI_POLARITY_HIGH. UART options are incorrect here.

2fill in blank

medium

Complete the code to send a byte over UART.

Embedded C

HAL_UART_Transmit(&huart1, &[1], 1, 1000);

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Atx_byte

Bdata

Cspi_data

Dbuffer

Attempts:

3 left

💡 Hint

Common Mistakes

Using SPI variable names instead of UART data variable.

The variable 'tx_byte' is typically used to hold the byte to send over UART.

3fill in blank

hard

Fix the error in the SPI data reception code by completing the blank.

Embedded C

HAL_SPI_Receive(&hspi2, [1], 1, 1000);

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A&rx_buffer

Brx_buffer

C&tx_buffer

Dtx_buffer

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the buffer variable without '&' causing runtime errors.

The receive function requires a pointer to the buffer where data will be stored, so '&rx_buffer' is correct.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that filters SPI data bytes greater than 128.

Embedded C

filtered_data = {byte: [1] for byte in spi_data if byte [2] 128}

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Abyte * 2

Bbyte + 1

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operator or incorrect value expression.

The comprehension doubles bytes greater than 128. So the condition is '>' and the value is 'byte * 2'.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps UART characters to their ASCII codes if code is less than 100.

Embedded C

ascii_map = [1]: ord([2]) for [3] in uart_chars if ord(char) < 100

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Achar

Dcode

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

We map each character 'char' to its ASCII code using ord(char) for chars in uart_chars with code less than 100.